Responses of Local Birds to the Offshore Wind Farms PAWP and OWEZ off the Dutch mainland coast

Offshore wind turbines are an alien element at sea, a “landscape” that is normally wide and open. Large, turning turbines might affect the local seabirds, that are dependent on the sea. One of the possible effects of offshore wind farms might be that the seabirds will be displaced from the sites, which would mean habitat destruction or at least habitat degradation for this group. All seabirds, being migratory, are protected under the EU Birds Directive. Yet, there are no studies into the question where wind farms should best be built (with respect to seabirds) or how they should be designed to minimize disturbance. This study compares the effects of two wind farms of different design in close proximity of each other. PAWP has a much higher turbine density (4.3 turbines / km2) than OWEZ (1.3/km2). This difference in turbine density probably constitutes the main difference in design between PAWP and OWEZ. The turbines deployed in PAWP (n=60) are Vestas V80 - 2 MW, at 59 m above mean sea level (amsl), with a rotor diameter of 80 m. Those in OWEZ (n=36) are Vestas V90 - 3MW turbines at 70 m amsl, with a rotor diameter of 90 m.